Gurugram, Sept. 27 -- A Central Industrial Security Force (CISF) inspector, his wife and an ambulance driver were killed after the ambulance in which they were travelling rear-ended a trailer truck at Badli Chowk near Pelpa village in Jhajjar on Saturday evening, police said. The deceased were identified as CISF inspector Sain Prakash, 59; his wife, Lakshmi, 58, both residents of Kaccha Babra Road in Jhajjar; and ambulance driver Pramod Jangra, 35, a resident of Jhajjar town. The accident took place around 6pm on the Gurugram-Jhajjar road, police said. Prakash's elder son, Pankaj Kumar, 35, who was also travelling in the ambulance, suffered multiple fractures and was critically injured. He is undergoing treatment at a private hospital in Jhajjar, police said. Investigators said Prakash had met with an accident on August 30 and was undergoing treatment at SGT Hospital in Chandu Budhera, Gurugram. Sub-inspector Sumit Kumar, station house officer of Badli police station, said Prakash had gone to the hospital to get stitches removed from his wounds. "After completing the procedure, they were returning home when the accident took place," he said. The SHO said Prakash, Lakshmi and Pankaj were seated in the rear compartment, and all four occupants were rushed to the civil hospital in Jhajjar. "However, looking at the critical condition of the couple, they were referred to PGIMS-Rohtak but were declared dead on arrival there," he said. "The driver was trapped inside the ambulance, and he could be extricated after several minutes of efforts. By the time he was rushed to Jhajjar Civil Hospital, he was declared dead too," he said. The SHO said Pankaj, an eyewitness, told police the trailer truck was moving erratically. "It had suddenly slowed down multiple times while moving ahead. The ambulance driver was not ever able to overtake," he said. Investigators said the truck driver suddenly braked hard, and the ambulance driver, unable to slow down in time, rammed the truck. The truck driver then abandoned the vehicle and fled on foot. An FIR was under process on Pankaj's statement against the unidentified truck under sections 106 (causing death by negligence), 281 (rash driving) and 125(b) (causing grievous hurt by act endangering life or personal safety of others) at Badli PS....